That's excellent. I heard that long exposures were the batteries quite a lot. (We were talking about 30 second espousers). Haw about 25 minutes? Do you take any special precautions dew to power with such pictures?

I have tried a few star/night shots on the bulb setting. And I haven't really timed them. But when I take a long exposure with my Canon 450 with the wide angle lens how ever long the exposure is the camera takes about the same amount of time for to process the image.

It's the waiting that's hard to see what I got. I do make sure that the battery has enough charge. Don't know what would happen if the battery dead while the camera was still processing the image.

I can't speek for canons, but what you are talking about in a nikon is called; 'high iso noise reduction'. This is an option that can be enabled. I believe that after shutter closes the camera then turns the sensor back on while the shutter remains closed, to record just the noise that the sensor is picking up. This second noise image is then subtracted from the initial image to reduce the noise. This is why the processing takes so long because the noise recording is the same legnth of time as the actual image.

This is my understanding of this, so feel free to correct me if I have got this wrong.

Earlier in the thred I stated the tha longest image I could take was 30 minutes. With further testing I have discovered that when using a wired cable release the shutter can be kept open longer. So it seems that it is just when using the wireless remote the limit is 30 minutes.